The genes for the Escherichia coli ribosomal proteins (r-proteins) are organized into at least 10 different transcription units, which are expressed coordinately. The molecular mechanisms responsible for this coordination will be investigated. It will be determined if any regulatory loops are involved, and the origins and targets of any loops will be identified. The general idea of the experiments is to perturb the coordination by selectively changing the rate of synthesis of a single r-protein without directly interfering with the synthesis of other proteins. After such a manipulation its consequences for the synthesis of other r-proteins, rRNA, translation factors, and RNA polymerase subunits will be studied. The experiments will performed with two different types of strains which allow the experimenter to have separate control of the expression of a given r-protein gene. First, the gene considered will be brought under the control of a promoter, which can be turned on by addition of inducers to the growth medium (the lactose promoter). Second, amber mutants in r-protein genes will be selected and their expression controlled by a temperature sensitive amber suppressor. Construction and analysis of many different strains in which different r-proteins genes are subjected to these types of manipulations will lead to "mapping" of the regulatory system coordinating the r-protein synthesis. After this "mapping" the molecular mechanisms will be investigated. Extract from cells which have been perturbed by the mentioned treatments will be added to a DNA dependent protein synthesizing in vitro system and the effects on the r-protein synthesis studied. Regulatory components will be identified by fractionation of the cell extracts.